Filtered feedthrough assembly having a capacitor ground metallization electrically connected to the gold braze portion sealing a ferrule peninsula to a matching insulator cutout

Abstract

A hermetically sealed filtered feedthrough assembly attachable to an AIMD includes an insulator hermetically sealing the opening of a ferrule with a gold braze. The ferrule includes a peninsula extending into the ferrule opening and the insulator has a cutout matching the peninsula. A sintered platinum-containing paste hermetically seals at least one via hole extending through the insulator. At least one capacitor is disposed on the device side. An active electrical connection electrically connects the capacitor active metallization to the sintered paste. A ground electrical connection electrically connects the capacitor ground metallization disposed within a capacitor ground passageway to the portion of the gold braze along the ferrule peninsula. The dielectric of the capacitor may be less than 1,000 k.

What is claimed is: 
     
       1. A hermetically sealed filtered feedthrough assembly attachable to an active implantable medical device (AIMD), the filtered feedthrough assembly comprising:
 a) a hermetic feedthrough, comprising:
 i) a metallic and electrically conductive ferrule configured to be installed in an opening of a housing of an AIMD, the ferrule separating a ferrule first side opposite a ferrule second side and comprising a ferrule opening extending to the ferrule first and second sides, wherein the ferrule comprises a peninsula extending into the ferrule opening; 
 ii) an insulator disposed at least partially within the ferrule opening, the insulator comprising an insulator first side corresponding to the ferrule first side and opposite an insulator second side corresponding to the ferrule second side, the insulator having a cutout matching the shape of the peninsula of the ferrule; 
 iii) at least one active via hole extending through the insulator to or adjacent to the insulator first and second sides; 
 iv) an electrically conductive material disposed within and hermetically sealing the at least one active via hole; and 
 v) a gold braze hermetically sealing the insulator to the ferrule including the ferrule peninsula received in the insulator cutout; 
 
 b) at least one internally grounded feedthrough capacitor disposed on or adjacent to the ferrule and insulator first sides, the internally grounded feedthrough capacitor comprising:
 i) a capacitor dielectric body; 
 ii) at least one active electrode plate and at least one ground electrode plate disposed in a capacitive relationship within the capacitor dielectric body; 
 iii) a first passageway and a second passageway, both passageways extending through the capacitor dielectric body; 
 iv) a capacitor active metallization disposed within the first passageway and being electrically connected to the at least one active electrode plate; and 
 v) a capacitor ground metallization disposed within the second passageway and being electrically connected to the at least one ground electrode plate, 
 vi) wherein a portion of the gold braze along a perimeter of the peninsula of the ferrule and the cutout of the insulator is spatially aligned directly under the capacitor ground metallization disposed within the second passageway of the internally ground feedthrough capacitor; and 
 
 c) an active electrical connection electrically connecting the electrically conductive material disposed in the at least one active via hole extending through the insulator to the capacitor active metallization; and 
 d) a ground electrical connection directly contacting both the spatially aligned portion of the gold braze along the perimeter of the peninsula of the ferrule and the capacitor ground metallization disposed within the second passageway of the internally grounded feedthrough capacitor. 
 
     
     
       2. The filtered feedthrough assembly of  claim 1 , wherein the electrically conductive material disposed within and hermetically sealing the at least one active via hole in the insulator is an electrically conductive sintered paste. 
     
     
       3. The filtered feedthrough assembly of  claim 2 , wherein the electrically conductive sintered paste and the insulator are characterized as having been co-fired. 
     
     
       4. The filtered feedthrough assembly of  claim 1 , wherein the electrically conductive material is a platinum-containing conductive pathway disposed within and hermetically sealing the at least one active via hole in the insulator. 
     
     
       5. The filtered feedthrough assembly of  claim 4 , wherein the platinum-containing conductive pathway disposed within and hermetically sealing the at least one active via hole is substantially flush with the insulator first side adjacent to the capacitor. 
     
     
       6. The filtered feedthrough assembly of  claim 1 , wherein the capacitor dielectric substrate does not have an outer perimeter metallization. 
     
     
       7. The filtered feedthrough assembly of  claim 1 , wherein the internally grounded feedthrough capacitor is a hybrid internally grounded feedthrough capacitor comprising at least a capacitor second ground metallization disposed on an outer surface of the capacitor dielectric substrate, wherein the capacitor second ground metallization is electrically connected to the at least one ground electrode plate, and wherein a second ground electrical connection electrically and physically connects at least a portion of the capacitor second ground metallization to the gold braze hermetically sealing the insulator to the ferrule. 
     
     
       8. The filtered feedthrough assembly of  claim 1 , wherein the platinum-containing conductive pathway disposed within the at least one active via hole comprises a nail-headed electrically conductive member with the nail head one of:
 i) facing the internally grounded feedthrough capacitor, 
 ii) facing the outwardly adjacent to the ferrule and insulator second sides, or 
 iii) facing both the internally grounded feedthrough capacitor and outwardly adjacent to the ferrule and insulator second sides, and 
 wherein the nail headed member is hermetically sealed in the at least one active via hole extending through the insulator by an electrically conductive platinum-containing material comprising the electrically conductive material in the active via hole. 
 
     
     
       9. The filtered feedthrough assembly of  claim 1 , wherein the platinum-containing conductive pathway disposed within the at least one active via hole in the insulator comprises a crimp post. 
     
     
       10. The filtered feedthrough assembly of  claim 1 , comprising an insulator metallization disposed on an outer surface of the insulator, wherein the gold braze contacts the ferrule and the insulator metallization. 
     
     
       11. The filtered feedthrough assembly of  claim 10 , wherein the insulator metallization comprises an adhesion layer disposed on the outer surface of the insulator and a gold braze wetting layer disposed on the adhesion layer. 
     
     
       12. The filtered feedthrough assembly of  claim 11 , wherein the adhesion layer is titanium and the wetting layer is molybdenum or niobium. 
     
     
       13. The filtered feedthrough assembly of  claim 1 , wherein the active electrical connection is selected from the group of a solder, a braze, an electrically conductive adhesive, and a thermal-setting conductive material. 
     
     
       14. The filtered feedthrough assembly of  claim 13 , wherein the active electrical connection is selected from a solder dot, a solder bump, a dot of thermal-setting conductive adhesive or epoxy, a bump of thermal-setting conductive adhesive or epoxy, and a ball grid array. 
     
     
       15. The filtered feedthrough assembly of  claim 1 , wherein the ground electrical connection is selected from the group of a solder, and a thermal-setting conductive material. 
     
     
       16. The filtered feedthrough assembly of  claim 1 , wherein the electrically conductive material disposed in the at least one active via hole extending through the insulator comprises a substantially pure platinum or a ceramic reinforced metal composite (CRMC) in a hermetically sealed relationship with the insulator. 
     
     
       17. The filtered feedthrough assembly of  claim 16 , wherein the hermetically sealed relationship between the substantially pure platinum or CRMC and the insulator comprises a tortuous and mutually conformal knitline having a glass that is at least about 60% silica. 
     
     
       18. The filtered feedthrough assembly of  claim 1 , wherein the ferrule comprises titanium. 
     
     
       19. The filtered feedthrough assembly of  claim 1 , wherein the insulator comprises at least 96% alumina. 
     
     
       20. The filtered feedthrough assembly of  claim 1 , wherein the ferrule is formed as a contiguous part of the housing of the AIMD. 
     
     
       21. The filtered feedthrough assembly of  claim 1 , wherein the capacitor dielectric body has a dielectric constant, k, that is greater than zero but less than 1000. 
     
     
       22. The filtered feedthrough assembly of  claim 1 , wherein the ferrule and insulator first sides are ferrule and insulator device sides and wherein the ferrule and insulator second sides are ferrule and insulator body fluid sides so that with the insulator hermetically sealed to the ferrule in the ferrule opening and with the ferrule installed in a housing for an AIMD, the ferrule and insulator first sides reside inside the housing and the ferrule and insulator second sides reside outside the housing, or
 wherein the ferrule and insulator first sides are ferrule and insulator body fluid sides and wherein the ferrule and insulator second sides are ferrule and insulator device sides so that with the insulator hermetically sealed to the ferrule in the ferrule opening and with the ferrule installed in a housing for an AIMD, the ferrule and insulator first sides reside outside the housing and the ferrule and insulator second sides reside inside the housing. 
 
     
     
       23. A hermetically sealed filtered feedthrough assembly attachable to an active implantable medical device (AIMD), the filtered feedthrough assembly comprising:
 a) a hermetic feedthrough, comprising:
 i) a metallic and electrically conductive ferrule configured to be installed in an opening of a housing of an AIMD, the ferrule having a ferrule body fluid side opposite a ferrule device side and comprising a ferrule opening extending to the ferrule body fluid and device sides, wherein the ferrule comprises a peninsula extending into the ferrule opening; 
 ii) an insulator disposed at least partially within the ferrule opening, the insulator comprising an insulator device side corresponding to the ferrule device side opposite an insulator body fluid side corresponding to the ferrule body fluid side, the insulator having a cutout matching the shape of the peninsula of the ferrule; 
 iii) at least one active via hole in the insulator extending to the insulator body fluid and device sides; 
 iv) an electrically conductive material disposed within and hermetically sealing the at least one active via hole; and 
 v) a gold braze hermetically sealing the insulator to the ferrule including the ferrule peninsula received in the insulator cutout; 
 
 b) an internally grounded feedthrough capacitor disposed on or adjacent to the ferrule and insulator first device sides, the internally grounded feedthrough capacitor comprising:
 i) at least one active electrode plate and at least one ground electrode plate disposed in a capacitive relationship within a capacitor dielectric substrate having a dielectric constant, k, that is greater than zero but less than 1000; 
 ii) a first passageway and a second passageway extending through the capacitor dielectric substrate; 
 iii) a capacitor active metallization disposed within the first passageway and being electrically connected to the at least one active electrode plate; 
 iv) a capacitor first ground metallization disposed within the second passageway and being electrically connected to the at least one ground electrode plate; and 
 v) a capacitor second ground metallization disposed on at least a portion of an outer surface of the capacitor dielectric substrate and being electrically connected to the at least one ground electrode plate, 
 vi) wherein a portion of the gold braze along a perimeter of the peninsula of the ferrule and the cutout of the insulator is spatially aligned directly under the capacitor first ground metallization disposed within the second passageway of the internally grounded feedthrough capacitor; 
 
 c) an active electrical connection electrically connecting the capacitor active metallization to the electrically conductive material disposed in the at least one active via hole extending through the insulator; 
 d) a first ground electrical connection directly contacting both the spatially aligned portion of the gold braze along the perimeter of the peninsula of the ferrule and the capacitor first ground metallization disposed within the second passageway of the internally grounded feedthrough capacitor; and 
 e) a second ground electrical connection electrically connecting at least a portion of the capacitor second ground metallization disposed on the outer surface of the capacitor dielectric substrate and being electrically connected to the at least one ground electrode plate to the gold braze. 
 
     
     
       24. The filtered feedthrough assembly of  claim 23 , wherein the electrically conductive material disposed within and hermetically sealing the at least one active via hole is substantially flush with a surface of the insulator adjacent to the capacitor. 
     
     
       25. The filtered feedthrough assembly of  claim 23 , wherein the platinum-containing conductive pathway disposed within the at least one active via hole comprises a nail headed electrically conductive member with the nail head facing the internally grounded feedthrough capacitor, and wherein the nail headed member is hermetically sealed in the at least one active via hole extending through the insulator by an electrically conductive platinum-containing material in the active via hole. 
     
     
       26. The filtered feedthrough assembly of  claim 25 , wherein the nail-headed member comprises a crimp post opposite the nail head. 
     
     
       27. The filtered feedthrough assembly of  claim 23 , comprising an insulator metallization disposed on an outer surface of the insulator, wherein the gold braze contacts the ferrule and the insulator metallization. 
     
     
       28. The filtered feedthrough assembly of  claim 23 , wherein the insulator metallization comprises an adhesion layer disposed on the outer surface of the insulator and a gold braze wetting layer disposed on the adhesion layer, and wherein the adhesion layer is titanium and the wetting layer is molybdenum or niobium. 
     
     
       29. The filtered feedthrough assembly of  claim 23 , wherein the active electrical connection is selected from the group of a solder, a braze, an electrically conductive adhesive, and a thermal-setting conductive material. 
     
     
       30. The filtered feedthrough assembly of  claim 23 , wherein the active electrical connection comprises a solder bump or a ball grid array. 
     
     
       31. The filtered feedthrough assembly of  claim 23 , wherein the ground electrical connection is selected from the group of a solder, and a thermal-setting conductive material. 
     
     
       32. The filtered feedthrough assembly of  claim 23 , wherein the electrically conductive material disposed in the at least one active via hole extending through the insulator of the hermetic feedthrough comprises a substantially pure platinum or a ceramic reinforced metal composite (CRMC) in a hermetically sealed relationship with the insulator. 
     
     
       33. The filtered feedthrough assembly of  claim 32 , wherein the hermetically sealed relationship between the substantially pure platinum or CRMC and the insulator comprises a tortuous and mutually conformal knitline having a glass that is at least about 60% silica. 
     
     
       34. The filtered feedthrough assembly of  claim 23 , wherein the ferrule comprises titanium. 
     
     
       35. The filtered feedthrough assembly of  claim 23 , wherein the insulator comprises at least 96% alumina. 
     
     
       36. The filtered feedthrough assembly of  claim 23 , wherein the ferrule is formed as a contiguous part of the housing of the AIMD.